This subject matter relates to a method, and its associated system and program storage device and computer program, for determining rock strength using sonic logging, and, in particular, for estimating and determining the rock strength from radial profiling of acoustic wave velocities using a Sonic Scanner Tool. The rock strength is used in a rock strength model of a Mechanical Earth Model (MEM) for the purpose of performing subsequent geomechanical calculations and generating predictions.
Evaluating rock strength from log measurements is fundamental to the analysis and prediction of geomechanical problems encountered in the petroleum industry. Examples of geomechanical problems include wellbore stability and fracturing of the formation during drilling that may lead to financial loss due to losses, kicks, stuck pipe, extra casing strings and sidetracks, and problems due to reservoir stress changes occurring during production, such as reservoir compaction, surface subsidence, formation fracturing, casing deformation and failure, sanding, reactivation of faults, and bedding parallel slip. In this specification, a new method is disclosed to estimate rock strength properties using ‘sonic radial profiling’, an operation that can be performed using a Sonic Scanner tool.
The following U.S. Patents are incorporated by reference into the specification of this application: U.S. Pat. No. 6,904,365 to Bratton et al.